I tried to solve myself this question by using Excel but it is not easy.

Imprudential, Inc., has an unfunded pension liability of $645 million that must be paid in 25 years. To access the value of the firm's stock, financial analysts want to discount this liability back to the present. If the relevant discount rate is 5.5 percent, what is the present value of this liability?

Present Value formula in excel = pv (rate, nper, pmt, [fv],[type]) right?

so

Future value = 645 million

rate = 5.50%

time = 25 year

pmt = ?

pv (5.50%,25,pmt,645 million)

How do I get the pmt????? i cannot solve this question because of it.